module main; // https://yamakasa3.hatenablog.com/entry/2018/06/24/214358 より import std; bool[] bit; dchar[][] a; RedBlackTree!(dchar[]) set; int n; void solve() { int l = 0, r = n - 1; auto t = new dchar[][](n); foreach (i; 0 .. n) { if (!bit[i]) { t[i] = a[l]; l++; } else { t[i] = a[r]; r--; } } set.insert(t.joiner.array); } void rec(int k) { if (k == n) { solve(); return; } rec(k + 1); bit[k] = true; rec(k + 1); bit[k] = false; } void main() { // 入力 auto s = readln.chomp; a = s.map!(a => [a]).array; n = s.length.to!int; bit = new bool[](n); set = new RedBlackTree!(dchar[])(); // 答えの計算と出力 rec(0); writeln(set.length); }